CYCLOSPORINE-A-INDUCED ALTERATIONS OF DENTINOGENESIS IN RAT MOLARS

Cyclosporin A (CsA), a widely used immunosuppressive drug, induces gin gival overgrowth and modifications of bone remodelling. The scope of t his study was to investigate the possible effect of CsA on dentin. Thi rty mg/kg/day of CsA were administered orally to male Sprague-Dawley r ats for nineteen weeks. The same number of control rats received oil-b ased vehicle solution. Rats were anesthetized, and tissues were fixed by an intracardiac perfusion of fixative solution. Mandibles were diss ected, demineralized, and processed for Epon embedding. Semi-thin sect ions of the first molars revealed alterations at the secondary dentin- pulp interface in four out of six experimental animals. The changes co nsisted of the formation of: 1) osteodentin spurs, in which the volume and interface with the secondary dentin varied from about 25,000 to 7 5,000 mu m(3) and from 1400 to 3530 mu m(2), respectively; 2) abnormal ly shaped and irregularly spaced incremental lines; and 3) numerous gl obular formations embedded in dentin or free in the pulp. These result s indicate that CsA induces abnormal mineralized matrix formation in d entin and in the peripheral part of the pulp in rat molars.